The risk of developing Type II diabetes is increased 16-fold by obesity and approximately 10-fold by aging. Dietary restriction (DR, long term, low calorie diets) has established efficacy in delaying aging and inreducing neoplastic disease in lab rodents. We have now identified 93 components of the sera metabolome that define a DR serotype - i.e., a metabolic serotype that reflects caloric intake. Multivariatepattern recognition analysishas identified profiles that distinguish ad libitum fed (AL) and DR rats (100% accuracy in training sets, mean >90% in test sets), and enabled construction of accurate models of intermediate intakes (1^=0.88) for individual rats. Initial sera proteome profiles also distinguish diet with 100% accuracy,. The robust, systemic effects of DR suggest that a subset of the metabolites in sera that distinguish diet will reflect, even across species, the physiological benefits of reduced caloric intake. We have established an interdisciplinary, multi-site team of investigators to test the two-part hypothesis that 1) serum metabolite profiles that reflect long-term caloric intake in rats will predict relative risk of human disease (specific test case: Type II diabetes), and;2) the components of these profiles are limited to a small subset of discrete metabolic pathways. Work on the latter sets the stage for understanding metabolic pathways involved in protective effects of DR against diabetes. The three Aims are: Aim 1. To complete characterization of metabolic serotypes based on both theproteome and the metabolome, and to adapt theseprofilesfor human epidemiological studies. Both individual serum constituents (proteins and metabolites) and their cognate metabolic profiles will be validated for studies using human samples. Aim 2. Todetermine the extent to which metabolic profiles that are reflective of or independent of lone-term caloric intake predict typeII diabetes in nested case control studies (Hypothesis, part 1) '<[unreadable][unreadable] We will evaluate the ability of expert systems trained to recognize serotypes reflectinglong term caloric . intake to determine relative risk for future Type II diabetes in sera from 1000 paired cases and controls from well-characterized humanpopulations (Nurses'Health Study). j ,-[unreadable] i i Aim 3 To determine the biochemical identity of critical serum markers (Hypothesis,part 2) [unreadable]. 'i. Mass spectroscopy will be used to identify critical protein and small molecule components ofmetabolic serotypes that characterize DR in rats and relative type II diabetes risk in humans '